1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device used, for example, for a light source of optical fiber communication, the semiconductor device manufactured using the manufacturing method and a system for manufacturing the semiconductor device.
2. Background Art
Japanese Patent Laid-Open No. 2001-91913 discloses a semiconductor device in which a laser section including an active layer and an optical modulator including a light absorption layer are monolithically formed. This semiconductor device is manufactured, for example, by forming an optical waveguide of the optical modulator first and then forming an optical waveguide of the laser section using a butt joint method.
To obtain a satisfactory current-optical output characteristic and high frequency characteristic, the difference value between a photoluminescence wavelength of the optical modulator and an oscillating wavelength of the laser section preferably has a predetermined value. An ideal difference value is determined in consideration of various characteristics.
As disclosed in Japanese Patent Laid-Open No. 2001-91913, by forming the optical modulator before the laser section, the optical modulator can be formed on a flat surface. This has an effect of making uniform the composition of the light absorption layer and stabilizing the photoluminescence wavelength of the optical modulator. However, there may be a case where a tolerable variation from the ideal difference value is only ±2 nm. In this case, the method disclosed in Japanese Patent Laid-Open No. 2001-91913 alone cannot reduce the variation in the difference value sufficiently.